1. Field of the Invention
This invention relates generally to a radio control driving circuit device, and more particularly to a radio control driving circuit device used for a model toy equipped with a d-c power supply, a receiver and two electric motors and travelling by receiving control signals transmitted from a transmitter, wherein transistors of the same type and used as two driving transistors.
2. Description of the Prior Art
In general, the model car, etc. having a radio control system has such a construction that two electric motors are equipped for separately driving each of the right and left driving wheels so that variable width control pulse signals transmitted by a transmitter can control the travelling direction and speed of the model car. In this type of driving circuit device, two transistors of the complementary type each having operating characteristics opposite to each other are usually used for each of the right and left motors. That is, each of the complementary type transistors is controlled by control pulse signals inputted from a single terminal, and two separate power supplies are used for driving the right and left wheels. In this circuit configuration, however, the difference in the characteristics of the complementary type transistors constituting the circuit and the difference in the degree of exhaustion between two batteries connected to the right and left motors may cause variations in revolution between the right and left motors.
In other words, since this circuit device is based on the operating principle that control pulses transmitted by a transmitter is received by a receiver on board the model car to drive the right and left wheels of the model car in accordance with the polarity and width of the received control pulses, the model car can travel straightforward by setting the duty factor of the control pulse width at 50%, thereby making the revolution of the right and left motors equal. In this type of conventional circuit device, however, the model car cannot necessarily travel straightforward at the duty factor of 50% due to the fact that the received control pulse signals are supplied to the complementary transistors, and that the right and left motors are driven by separate batteries.